Simon was a common name at the time of the beginning of the Church of Christ, and many traditions and legends arose around the character mentioned in this biblical passage, which came to be nicknamed "the Sorcerer". In English and some other languages the word "simony" derived from that person to mean the buying or selling of spiritual things, or of those which are material but are linked to what is spiritual.
This man, and many others before the time Gnosticism intensified, practiced magic or witchcraft that exploited the superstition and credulity of the people in Samaria, earning for him fame and money. People said that he was the "great power of God", a spark of the greater deity, impersonating God himself.
But many of the people believed in Philip when he came preaching about the kingdom of God and the name of Jesus Christ, and were baptized. Also Simon, who then diligently attended Philip, astonished with what he could do. From what followed, we understand that Simon had not really been converted but just wanted to find out how Philip did the miracles.
When the Apostles, all in Jerusalem, knew what was happening in Samaria, they sent Peter and John to them. It is interesting to see that the decision was taken in group: these two remarkable apostles did not act on their own. Arriving there, they saw that the Holy Spirit had not come upon any of the Samaritans, unlike the Jewish converts, upon whom He came soon after their conversion and baptism (Acts 2:38).
Peter and John therefore prayed asking that these Samaritans might receive the Holy Spirit, and laid hands on them, a sign of solidarity used among the Jews. The Samaritans then received the Holy Spirit.
The Bible does not explain why the Samaritans had not yet received the Holy Spirit as the Jews, although they believed and were baptized, but it is likely that this was in order to manifest the communion of Jews and Samaritans in the church of Christ. Jews did not get on well with the Samaritans, so to prevent this attitude from continuing in the church, before giving his Spirit God sent the Apostles to pray for the Samaritans, and to place their hands on them to prove that they participated in the same Spirit. Nothing is said about the gift of tongues, as if it were evidence that they had received the Holy Spirit.
It is clear here that to go through the waters of baptism or any other ceremony does not save, nor does it make the Holy Spirit come into a person's life, much less does it make him a member of the church of Christ.
Evidently Simon was not among those over whom the apostles had been praying and laying their hands, and he did not understand its meaning. When he saw it done, he thought that the Holy Spirit was given like that (it was not, see the example for Cornelius in Acts 10:44). His greed immediately gave him an idea he thought profitable: to buy this power from the Apostles, since he thought that having it, he would have the opportunity to enrich himself by selling it to others for a good price as he probably did with his magic, and he would maintain his prestige, which was now at stake.
Despite his confession of faith and baptism, Simon believed that "everything has a price" as it is said nowadays. It is normal in a world of bribes, materialism and search of riches. But Simon was surprised by a severe rebuke from Peter.
Peter saw, from the proposal made to him, that the heart of Simon “was not right in the sight of God” despite his profession of faith and baptism, and that he was destined to eternal perdition (John 3:16). He wasn't really converted, because:
He was destined to eternal perdition: "your money perish with you" (no true believer will perish – John 3:16).
He was not in communion with the church: "You have neither part nor portion in this matter".
He had not accepted the word of God: "his heart was not straight before God" (see Luke 8:15).
He manifested lack of regeneration: he was "poisoned by bitterness and bound by iniquity.”
The power of the Holy Spirit has never been for sale. Neither can other blessings of God, such as material prosperity in this life, ever be purchased. In the Kingdom of God, of which partake those who have been sanctified by the grace of God through faith in Jesus Christ here on Earth, all have the Holy Spirit. Simon did not have it, and Peter told him that he needed to repent and beg the Lord to be forgiven for having this covetous idea. Peter still seemed to be in doubt if Simon would be forgiven by God.
God is gracious, full of compassion and great in mercy (Psalm 145:8). The Lord Jesus taught that “Every sin and blasphemy will be forgiven men, but the blasphemy against the Spirit will not be forgiven men." (Matthew 12:31). Would Peter be thinking that Simon might have committed this sin? Peter left the hope for forgiveness open, provided Simon repented and sought forgiveness from the Lord. Simon was frightened, but gave no sign of repentance, only asked for the Apostles to pray to the Lord for him, that none of the things spoken by Peter might come upon him. It was evident that Simon had never changed his life, and continued on his path away from God, despite his profession of faith and baptism.
This is the attitude of the crowds who don't want have a personal commitment with God, and turn to the intermediation of false priests, the dead "saints" and so on, trying to obtain the forgiveness of their sins in this way. But the Lord Jesus said clearly: "he who does not believe (in the Gospel) will be condemned" (Mark 16:16). Salvation is not for sale, and God is righteous and will punish those who reject the forgiveness of their sins through faith in Jesus Christ.
Nothing more is known about Simon the Magician, because his name no longer appears in the Scriptures. But the report made about him is a solemn warning that echoes throughout the ages against simony, so in vogue in our times when merchandising of the things of God fills the temples of sellers of prosperity and other "graces". Will they achieve the forgiveness of God through repentance? The Apostle Peter was not sure of this in the case of Simon.
We must beware lest this terrible evil comes into our midst.
But there was a certain man called Simon, who previously practiced sorcery in the city and astonished the people of Samaria, claiming that he was someone great,
10 to whom they all gave heed, from the least to the greatest, saying, "This man is the great power of God."
11 And they heeded him because he had astonished them with his sorceries for a long time.
12 But when they believed Philip as he preached the things concerning the kingdom of God and the name of Jesus Christ, both men and women were baptized.
13 Then Simon himself also believed; and when he was baptized he continued with Philip, and was amazed, seeing the miracles and signs which were done.
14 Now when the apostles who were at Jerusalem heard that Samaria had received the word of God, they sent Peter and John to them,
15 who, when they had come down, prayed for them that they might receive the Holy Spirit.
16 For as yet He had fallen upon none of them. They had only been baptized in the name of the Lord Jesus.
17 Then they laid hands on them, and they received the Holy Spirit.
18 And when Simon saw that through the laying on of the apostles' hands the Holy Spirit was given, he offered them money,
19 saying, "Give me this power also, that anyone on whom I lay hands may receive the Holy Spirit."
20 But Peter said to him, "Your money perish with you, because you thought that the gift of God could be purchased with money!
21 You have neither part nor portion in this matter, for your heart is not right in the sight of God.
22 Repent therefore of this your wickedness, and pray God if perhaps the thought of your heart may be forgiven you.
23 For I see that you are poisoned by bitterness and bound by iniquity."
24 Then Simon answered and said, "Pray to the Lord for me, that none of the things which you have spoken may come upon me."
25 So when they had testified and preached the word of the Lord, they returned to Jerusalem, preaching the gospel in many villages of the Samaritans.
Acts chapter 8 verses 9 to 25